Circuit Breaker Closing Time Detection via Voltage Jump Analysis

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Solution Overview

Problem

Current methods for determining the closing time of a circuit breaker's phase voltage signal are inaccurate due to reliance on fixed threshold values, which can lead to incorrect switch-on times, especially when interference signals are present.

Innovation Solution

A method that involves sampling voltage signals, identifying a voltage jump point by analyzing slope changes, and determining the closing time based on the sampling time of the jump point, with a second time period defined by consecutive voltage thresholds, allowing for more precise switch-on time detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a fixed threshold value is used to determine the switch-on time, then the method is simple to implement, but the measurement precision of the closing time deteriorates due to interference signals

Engineering Contradiction:
Improvesimplicity of implementationVSAvoidprecision of closing time
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameter from a fixed voltage threshold to a dynamic threshold based on the rate of change of voltage (dv/dt). By detecting the voltage jump point where the rate of change exceeds a preset threshold, the method adapts to different operating conditions and interference levels, thereby improving measurement precision while maintaining implementation simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary action by setting a search window around the expected closing time based on the closing time distribution characteristics. This preliminary definition of the search range allows the algorithm to focus detection efforts on the most probable region, improving both precision and computational efficiency

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the entire voltage signal is searched for the voltage jump point, then no search range limitation is applied, but the productivity deteriorates due to increased computational complexity

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidaccuracy of voltage jump point detection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the voltage signal search space into three parts: a search window before the expected closing time, a middle window around the expected closing time, and a search window after. By dividing the search into segments with different detection strategies, the method maintains high detection accuracy while significantly reducing the computational burden of searching the entire signal

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different detection thresholds and strategies for different time regions. The middle window uses a lower threshold for sensitive detection, while the outer windows use higher thresholds, creating a localized detection approach that optimizes both accuracy and efficiency for each region

Inventive Principle:
Principle #3Local quality

3Loss of time

If a narrow search window is used around the expected closing time, then the processing time is reduced, but the measurement precision may deteriorate if the actual closing time falls outside the window

Engineering Contradiction:
Improveprocessing timeVSAvoidaccuracy of closing time
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the search window size adaptive rather than fixed. The window size is dynamically adjusted based on the actual voltage signal characteristics and the detected voltage jump point position. This allows the search window to expand or contract as needed, ensuring that the actual closing time is always captured while minimizing unnecessary processing of distant regions

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3879549B1Method and device for determining closing time of circuit breaker, and computer-readable medium
Publication Date: 2024.04.24 SIEMENS AG
  • EP3879549B1 patent drawingFigure 1
  • EP3879549B1 patent drawingFigure 2
  • EP3879549B1 patent drawingFigure 3

AI summary

The present invention provides a method and a device for determining the closing time of a circuit breaker, and a computer-readable medium, the circuit breaker outputting a three-phase voltage signal, the method comprising: sampling a voltage signal of a target phase in the three-phase voltage signal of the circuit breaker; determining a first time period according to a voltage value of the sampled voltage signal, a voltage signal in the first time period comprising a voltage jump point of the voltage value; finding a voltage jump point of a voltage value in the first time period according to a change in the voltage value of the voltage signal in the first time period; and determining the closing time of a target phase of the circuit breaker according to the found sampling time of the voltage jump point. The present invention provides a method and device for determining the closing time of a circuit breaker, and a computer-readable medium, capable of determining more accurately the closing time of each phase of a circuit breaker.